Ingot shape control by dynamic head in electromagnetic casting

Abstract

A method and apparatus is disclosed for electromagnetic casting of metal and alloy ingots of desired shape having portions of small radius of curvature. An open-ended container or hot-top having spaced internal baffles is placed before the electromagnetic induction station of the casting apparatus to provide desired metal flow patterns. Also disclosed is a downspout having nozzle portions which provide preferred directionality to supplied molten metal.

What is claimed is: 
     
       1. In an apparatus for electromagnetic forming of molten metals or alloys into a casting of desired shape having at least one portion of small radius of curvature comprising: means for providing said molten metals or alloys;   means comprising a hot-top for receiving said molten metals or alloys, said hot-top including at least one corner and having approximately the same cross-section as said casting;   means comprising an electromagnetic casting station for forming said molten metals or alloys as they emerge from said hot-top into said casting; the improvement comprising:   means associated with said hot-top adapted for increasing the dynamic pressure of said molten metals or alloys at said hot-top corner by preferentially directing molten metal or alloy flow toward said hot-top corner.   
     
     
       2. An apparatus as in claim 1 wherein said hot-top includes at least one internal baffle for preferentially directing said molten metal or allow flow. 
     
     
       3. An apparatus as in claim 2 wherein said hot-top includes two internal spaced baffles, each of said baffles being located on opposed internal walls of said hot-top. 
     
     
       4. An apparatus as in claim 2 wherein said hot-top includes four internal spaced baffles, each of said baffles being located on individual internal walls of said hot-top. 
     
     
       5. An apparatus as in claim 1 wherein said means for pouring comprises downspout means having at least one nozzle. 
     
     
       6. An apparatus as in claim 2 wherein said means for pouring comprises downspout means having at least one nozzle. 
     
     
       7. An apparatus as in claim 4 wherein said hot-top is of approximately rectangular shape with four corners. 
     
     
       8. An apparatus as in claim 7 wherein said means for pouring comprises downspout means having four nozzles, each of said nozzles providing directionality to the molten metal or alloy being poured into said hot-top toward said corners. 
     
     
       9. An apparatus as in claim 2 wherein said at least one baffle is located at the bottom of said hot-top. 
     
     
       10. An apparatus as in claim 2 wherein said at least one baffle is located greater than about 1/4" from the bottom of said hot-top. 
     
     
       11. An apparatus as in claim 9 wherein said hot-top has a height greater than about 3/4". 
     
     
       12. An apparatus as in claim 2 wherein said at least one baffle has a thickness of from about 1/2" to about 1". 
     
     
       13. An apparatus as in claim 1 including means for partially closing the inlet end of said hot-top to provide means for removal of undesirable particles from said poured molten metal or alloy. 
     
     
       14. An apparatus as in claim 13 wherein said means for partially closing the inlet end of said hot-top comprises an open pored ceramic foam filter in spanning engagement with said hot-top. 
     
     
       15. An apparatus as in claim 13 wherein said means for partially closing the inlet end of said hot-top comprises an apertured screen in spanning engagement with said hot-top. 
     
     
       16. In a process for electromagnetic forming of molten metals or alloys into a casting of desired shape having at least one portion of small radius of curvature comprising: providing a hot-top having approximately the same cross-section as said casting;   pouring said molten metal or alloy into said hot-top;   providing an electromagnetic casting station; and forming said molten metal or alloy into said casting in said electromagnetic casting station as it emerges from said hot-top, the improvement which comprises:   increasing the dynamic pressure of said molten metals or alloys at said portion of small radius of curvature by preferentially directing metal or alloy flow in said forming casting toward said portion of small radius of curvature,   whereby a casting of desired shape having said at least one portion of small radius of curvature is formed.   
     
     
       17. A process as in claim 16 wherein said step of increasing the dynamic pressure of said molten metals or alloys is carried out by providing directionality to the molten metal or alloy being poured toward said forming casting portion of small radius of curvature. 
     
     
       18. A process as in claim 17 wherein said casting comprises a rectangular slab ingot and said step of increasing the dynamic pressure of said molten metals or alloys is carried out by providing directionality to said molten metal or alloy being poured toward each corner of said forming ingot. 
     
     
       19. A process as in claim 16 wherein said hot-top is provided with at least one baffle along the internal walls thereof and said step of increasing the dynamic pressure of said molten metals or alloys is carried out by causing metal or alloy to preferentially flow about said at least one baffle. 
     
     
       20. A process as in claim 16 wherein said casting comprises a rectangular slab ingot, and said hot-top is provided with four spaced baffles, each of said baffles being located on individual internal walls of said hot-top, whereby said step of increasing the dynamic pressure of said molten metals or alloys is carried out by causing metal or alloy to preferentially flow about said baffles toward the corners of said forming ingot. 
     
     
       21. In a process for electromagnetic forming of molten metals or alloys into a casting of desired shape having at least one portion of small radius of curvature comprising: providing an electromagnetic casting station;   pouring said molten metal or alloy into said electromagnetic casting station;   forming said molten metal or alloy in said electromagnetic casting station to form said casting; the improvement comprising:   increasing the dynamic pressure of said molten metals or alloys at said portion of small radius of curvature by preferentially directing said molten metal or alloy flow toward said portion of small radius of curvature as said molten metal or alloy is poured,   whereby a casting of desired shape having said at least one portion of small radius of curvature is formed.   
     
     
       22. A process as in claim 21 wherein said casting comprises a rectangular slab ingot and said step of increasing the dynamic pressure of said molten metals or alloys is carried out by providing directionality to said molten metal or alloy being poured into said hot-top toward the corners of said forming ingot.